xref: /openbmc/linux/drivers/net/wireless/ath/ath5k/qcu.c (revision 565d76cb)
1 /*
2  * Copyright (c) 2004-2008 Reyk Floeter <reyk@openbsd.org>
3  * Copyright (c) 2006-2008 Nick Kossifidis <mickflemm@gmail.com>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  *
17  */
18 
19 /********************************************\
20 Queue Control Unit, DFS Control Unit Functions
21 \********************************************/
22 
23 #include "ath5k.h"
24 #include "reg.h"
25 #include "debug.h"
26 #include "base.h"
27 
28 
29 /******************\
30 * Helper functions *
31 \******************/
32 
33 /*
34  * Get number of pending frames
35  * for a specific queue [5211+]
36  */
37 u32 ath5k_hw_num_tx_pending(struct ath5k_hw *ah, unsigned int queue)
38 {
39 	u32 pending;
40 	AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);
41 
42 	/* Return if queue is declared inactive */
43 	if (ah->ah_txq[queue].tqi_type == AR5K_TX_QUEUE_INACTIVE)
44 		return false;
45 
46 	/* XXX: How about AR5K_CFG_TXCNT ? */
47 	if (ah->ah_version == AR5K_AR5210)
48 		return false;
49 
50 	pending = ath5k_hw_reg_read(ah, AR5K_QUEUE_STATUS(queue));
51 	pending &= AR5K_QCU_STS_FRMPENDCNT;
52 
53 	/* It's possible to have no frames pending even if TXE
54 	 * is set. To indicate that q has not stopped return
55 	 * true */
56 	if (!pending && AR5K_REG_READ_Q(ah, AR5K_QCU_TXE, queue))
57 		return true;
58 
59 	return pending;
60 }
61 
62 /*
63  * Set a transmit queue inactive
64  */
65 void ath5k_hw_release_tx_queue(struct ath5k_hw *ah, unsigned int queue)
66 {
67 	if (WARN_ON(queue >= ah->ah_capabilities.cap_queues.q_tx_num))
68 		return;
69 
70 	/* This queue will be skipped in further operations */
71 	ah->ah_txq[queue].tqi_type = AR5K_TX_QUEUE_INACTIVE;
72 	/*For SIMR setup*/
73 	AR5K_Q_DISABLE_BITS(ah->ah_txq_status, queue);
74 }
75 
76 /*
77  * Make sure cw is a power of 2 minus 1 and smaller than 1024
78  */
79 static u16 ath5k_cw_validate(u16 cw_req)
80 {
81 	u32 cw = 1;
82 	cw_req = min(cw_req, (u16)1023);
83 
84 	while (cw < cw_req)
85 		cw = (cw << 1) | 1;
86 
87 	return cw;
88 }
89 
90 /*
91  * Get properties for a transmit queue
92  */
93 int ath5k_hw_get_tx_queueprops(struct ath5k_hw *ah, int queue,
94 		struct ath5k_txq_info *queue_info)
95 {
96 	memcpy(queue_info, &ah->ah_txq[queue], sizeof(struct ath5k_txq_info));
97 	return 0;
98 }
99 
100 /*
101  * Set properties for a transmit queue
102  */
103 int ath5k_hw_set_tx_queueprops(struct ath5k_hw *ah, int queue,
104 				const struct ath5k_txq_info *qinfo)
105 {
106 	struct ath5k_txq_info *qi;
107 
108 	AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);
109 
110 	qi = &ah->ah_txq[queue];
111 
112 	if (qi->tqi_type == AR5K_TX_QUEUE_INACTIVE)
113 		return -EIO;
114 
115 	/* copy and validate values */
116 	qi->tqi_type = qinfo->tqi_type;
117 	qi->tqi_subtype = qinfo->tqi_subtype;
118 	qi->tqi_flags = qinfo->tqi_flags;
119 	/*
120 	 * According to the docs: Although the AIFS field is 8 bit wide,
121 	 * the maximum supported value is 0xFC. Setting it higher than that
122 	 * will cause the DCU to hang.
123 	 */
124 	qi->tqi_aifs = min(qinfo->tqi_aifs, (u8)0xFC);
125 	qi->tqi_cw_min = ath5k_cw_validate(qinfo->tqi_cw_min);
126 	qi->tqi_cw_max = ath5k_cw_validate(qinfo->tqi_cw_max);
127 	qi->tqi_cbr_period = qinfo->tqi_cbr_period;
128 	qi->tqi_cbr_overflow_limit = qinfo->tqi_cbr_overflow_limit;
129 	qi->tqi_burst_time = qinfo->tqi_burst_time;
130 	qi->tqi_ready_time = qinfo->tqi_ready_time;
131 
132 	/*XXX: Is this supported on 5210 ?*/
133 	/*XXX: Is this correct for AR5K_WME_AC_VI,VO ???*/
134 	if ((qinfo->tqi_type == AR5K_TX_QUEUE_DATA &&
135 		((qinfo->tqi_subtype == AR5K_WME_AC_VI) ||
136 		 (qinfo->tqi_subtype == AR5K_WME_AC_VO))) ||
137 	     qinfo->tqi_type == AR5K_TX_QUEUE_UAPSD)
138 		qi->tqi_flags |= AR5K_TXQ_FLAG_POST_FR_BKOFF_DIS;
139 
140 	return 0;
141 }
142 
143 /*
144  * Initialize a transmit queue
145  */
146 int ath5k_hw_setup_tx_queue(struct ath5k_hw *ah, enum ath5k_tx_queue queue_type,
147 		struct ath5k_txq_info *queue_info)
148 {
149 	unsigned int queue;
150 	int ret;
151 
152 	/*
153 	 * Get queue by type
154 	 */
155 	/* 5210 only has 2 queues */
156 	if (ah->ah_capabilities.cap_queues.q_tx_num == 2) {
157 		switch (queue_type) {
158 		case AR5K_TX_QUEUE_DATA:
159 			queue = AR5K_TX_QUEUE_ID_NOQCU_DATA;
160 			break;
161 		case AR5K_TX_QUEUE_BEACON:
162 		case AR5K_TX_QUEUE_CAB:
163 			queue = AR5K_TX_QUEUE_ID_NOQCU_BEACON;
164 			break;
165 		default:
166 			return -EINVAL;
167 		}
168 	} else {
169 		switch (queue_type) {
170 		case AR5K_TX_QUEUE_DATA:
171 			for (queue = AR5K_TX_QUEUE_ID_DATA_MIN;
172 				ah->ah_txq[queue].tqi_type !=
173 				AR5K_TX_QUEUE_INACTIVE; queue++) {
174 
175 				if (queue > AR5K_TX_QUEUE_ID_DATA_MAX)
176 					return -EINVAL;
177 			}
178 			break;
179 		case AR5K_TX_QUEUE_UAPSD:
180 			queue = AR5K_TX_QUEUE_ID_UAPSD;
181 			break;
182 		case AR5K_TX_QUEUE_BEACON:
183 			queue = AR5K_TX_QUEUE_ID_BEACON;
184 			break;
185 		case AR5K_TX_QUEUE_CAB:
186 			queue = AR5K_TX_QUEUE_ID_CAB;
187 			break;
188 		case AR5K_TX_QUEUE_XR_DATA:
189 			if (ah->ah_version != AR5K_AR5212)
190 				ATH5K_ERR(ah->ah_sc,
191 					"XR data queues only supported in"
192 					" 5212!\n");
193 			queue = AR5K_TX_QUEUE_ID_XR_DATA;
194 			break;
195 		default:
196 			return -EINVAL;
197 		}
198 	}
199 
200 	/*
201 	 * Setup internal queue structure
202 	 */
203 	memset(&ah->ah_txq[queue], 0, sizeof(struct ath5k_txq_info));
204 	ah->ah_txq[queue].tqi_type = queue_type;
205 
206 	if (queue_info != NULL) {
207 		queue_info->tqi_type = queue_type;
208 		ret = ath5k_hw_set_tx_queueprops(ah, queue, queue_info);
209 		if (ret)
210 			return ret;
211 	}
212 
213 	/*
214 	 * We use ah_txq_status to hold a temp value for
215 	 * the Secondary interrupt mask registers on 5211+
216 	 * check out ath5k_hw_reset_tx_queue
217 	 */
218 	AR5K_Q_ENABLE_BITS(ah->ah_txq_status, queue);
219 
220 	return queue;
221 }
222 
223 
224 /*******************************\
225 * Single QCU/DCU initialization *
226 \*******************************/
227 
228 /*
229  * Set tx retry limits on DCU
230  */
231 void ath5k_hw_set_tx_retry_limits(struct ath5k_hw *ah,
232 				  unsigned int queue)
233 {
234 	/* Single data queue on AR5210 */
235 	if (ah->ah_version == AR5K_AR5210) {
236 		struct ath5k_txq_info *tq = &ah->ah_txq[queue];
237 
238 		if (queue > 0)
239 			return;
240 
241 		ath5k_hw_reg_write(ah,
242 			(tq->tqi_cw_min << AR5K_NODCU_RETRY_LMT_CW_MIN_S)
243 			| AR5K_REG_SM(ah->ah_retry_long,
244 				      AR5K_NODCU_RETRY_LMT_SLG_RETRY)
245 			| AR5K_REG_SM(ah->ah_retry_short,
246 				      AR5K_NODCU_RETRY_LMT_SSH_RETRY)
247 			| AR5K_REG_SM(ah->ah_retry_long,
248 				      AR5K_NODCU_RETRY_LMT_LG_RETRY)
249 			| AR5K_REG_SM(ah->ah_retry_short,
250 				      AR5K_NODCU_RETRY_LMT_SH_RETRY),
251 			AR5K_NODCU_RETRY_LMT);
252 	/* DCU on AR5211+ */
253 	} else {
254 		ath5k_hw_reg_write(ah,
255 			AR5K_REG_SM(ah->ah_retry_long,
256 				    AR5K_DCU_RETRY_LMT_RTS)
257 			| AR5K_REG_SM(ah->ah_retry_long,
258 				      AR5K_DCU_RETRY_LMT_STA_RTS)
259 			| AR5K_REG_SM(max(ah->ah_retry_long, ah->ah_retry_short),
260 				      AR5K_DCU_RETRY_LMT_STA_DATA),
261 			AR5K_QUEUE_DFS_RETRY_LIMIT(queue));
262 	}
263 }
264 
265 /**
266  * ath5k_hw_reset_tx_queue - Initialize a single hw queue
267  *
268  * @ah The &struct ath5k_hw
269  * @queue The hw queue number
270  *
271  * Set DFS properties for the given transmit queue on DCU
272  * and configures all queue-specific parameters.
273  */
274 int ath5k_hw_reset_tx_queue(struct ath5k_hw *ah, unsigned int queue)
275 {
276 	struct ath5k_txq_info *tq = &ah->ah_txq[queue];
277 
278 	AR5K_ASSERT_ENTRY(queue, ah->ah_capabilities.cap_queues.q_tx_num);
279 
280 	tq = &ah->ah_txq[queue];
281 
282 	/* Skip if queue inactive or if we are on AR5210
283 	 * that doesn't have QCU/DCU */
284 	if ((ah->ah_version == AR5K_AR5210) ||
285 	(tq->tqi_type == AR5K_TX_QUEUE_INACTIVE))
286 		return 0;
287 
288 	/*
289 	 * Set contention window (cw_min/cw_max)
290 	 * and arbitrated interframe space (aifs)...
291 	 */
292 	ath5k_hw_reg_write(ah,
293 		AR5K_REG_SM(tq->tqi_cw_min, AR5K_DCU_LCL_IFS_CW_MIN) |
294 		AR5K_REG_SM(tq->tqi_cw_max, AR5K_DCU_LCL_IFS_CW_MAX) |
295 		AR5K_REG_SM(tq->tqi_aifs, AR5K_DCU_LCL_IFS_AIFS),
296 		AR5K_QUEUE_DFS_LOCAL_IFS(queue));
297 
298 	/*
299 	 * Set tx retry limits for this queue
300 	 */
301 	ath5k_hw_set_tx_retry_limits(ah, queue);
302 
303 
304 	/*
305 	 * Set misc registers
306 	 */
307 
308 	/* Enable DCU to wait for next fragment from QCU */
309 	AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_DFS_MISC(queue),
310 				AR5K_DCU_MISC_FRAG_WAIT);
311 
312 	/* On Maui and Spirit use the global seqnum on DCU */
313 	if (ah->ah_mac_version < AR5K_SREV_AR5211)
314 		AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_DFS_MISC(queue),
315 					AR5K_DCU_MISC_SEQNUM_CTL);
316 
317 	/* Constant bit rate period */
318 	if (tq->tqi_cbr_period) {
319 		ath5k_hw_reg_write(ah, AR5K_REG_SM(tq->tqi_cbr_period,
320 					AR5K_QCU_CBRCFG_INTVAL) |
321 					AR5K_REG_SM(tq->tqi_cbr_overflow_limit,
322 					AR5K_QCU_CBRCFG_ORN_THRES),
323 					AR5K_QUEUE_CBRCFG(queue));
324 
325 		AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
326 					AR5K_QCU_MISC_FRSHED_CBR);
327 
328 		if (tq->tqi_cbr_overflow_limit)
329 			AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
330 					AR5K_QCU_MISC_CBR_THRES_ENABLE);
331 	}
332 
333 	/* Ready time interval */
334 	if (tq->tqi_ready_time && (tq->tqi_type != AR5K_TX_QUEUE_CAB))
335 		ath5k_hw_reg_write(ah, AR5K_REG_SM(tq->tqi_ready_time,
336 					AR5K_QCU_RDYTIMECFG_INTVAL) |
337 					AR5K_QCU_RDYTIMECFG_ENABLE,
338 					AR5K_QUEUE_RDYTIMECFG(queue));
339 
340 	if (tq->tqi_burst_time) {
341 		ath5k_hw_reg_write(ah, AR5K_REG_SM(tq->tqi_burst_time,
342 					AR5K_DCU_CHAN_TIME_DUR) |
343 					AR5K_DCU_CHAN_TIME_ENABLE,
344 					AR5K_QUEUE_DFS_CHANNEL_TIME(queue));
345 
346 		if (tq->tqi_flags & AR5K_TXQ_FLAG_RDYTIME_EXP_POLICY_ENABLE)
347 			AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
348 					AR5K_QCU_MISC_RDY_VEOL_POLICY);
349 	}
350 
351 	/* Enable/disable Post frame backoff */
352 	if (tq->tqi_flags & AR5K_TXQ_FLAG_BACKOFF_DISABLE)
353 		ath5k_hw_reg_write(ah, AR5K_DCU_MISC_POST_FR_BKOFF_DIS,
354 					AR5K_QUEUE_DFS_MISC(queue));
355 
356 	/* Enable/disable fragmentation burst backoff */
357 	if (tq->tqi_flags & AR5K_TXQ_FLAG_FRAG_BURST_BACKOFF_ENABLE)
358 		ath5k_hw_reg_write(ah, AR5K_DCU_MISC_BACKOFF_FRAG,
359 					AR5K_QUEUE_DFS_MISC(queue));
360 
361 	/*
362 	 * Set registers by queue type
363 	 */
364 	switch (tq->tqi_type) {
365 	case AR5K_TX_QUEUE_BEACON:
366 		AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
367 				AR5K_QCU_MISC_FRSHED_DBA_GT |
368 				AR5K_QCU_MISC_CBREXP_BCN_DIS |
369 				AR5K_QCU_MISC_BCN_ENABLE);
370 
371 		AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_DFS_MISC(queue),
372 				(AR5K_DCU_MISC_ARBLOCK_CTL_GLOBAL <<
373 				AR5K_DCU_MISC_ARBLOCK_CTL_S) |
374 				AR5K_DCU_MISC_ARBLOCK_IGNORE |
375 				AR5K_DCU_MISC_POST_FR_BKOFF_DIS |
376 				AR5K_DCU_MISC_BCN_ENABLE);
377 		break;
378 
379 	case AR5K_TX_QUEUE_CAB:
380 		/* XXX: use BCN_SENT_GT, if we can figure out how */
381 		AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
382 					AR5K_QCU_MISC_FRSHED_DBA_GT |
383 					AR5K_QCU_MISC_CBREXP_DIS |
384 					AR5K_QCU_MISC_CBREXP_BCN_DIS);
385 
386 		ath5k_hw_reg_write(ah, ((tq->tqi_ready_time -
387 					(AR5K_TUNE_SW_BEACON_RESP -
388 					AR5K_TUNE_DMA_BEACON_RESP) -
389 				AR5K_TUNE_ADDITIONAL_SWBA_BACKOFF) * 1024) |
390 					AR5K_QCU_RDYTIMECFG_ENABLE,
391 					AR5K_QUEUE_RDYTIMECFG(queue));
392 
393 		AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_DFS_MISC(queue),
394 					(AR5K_DCU_MISC_ARBLOCK_CTL_GLOBAL <<
395 					AR5K_DCU_MISC_ARBLOCK_CTL_S));
396 		break;
397 
398 	case AR5K_TX_QUEUE_UAPSD:
399 		AR5K_REG_ENABLE_BITS(ah, AR5K_QUEUE_MISC(queue),
400 					AR5K_QCU_MISC_CBREXP_DIS);
401 		break;
402 
403 	case AR5K_TX_QUEUE_DATA:
404 	default:
405 			break;
406 	}
407 
408 	/* TODO: Handle frame compression */
409 
410 	/*
411 	 * Enable interrupts for this tx queue
412 	 * in the secondary interrupt mask registers
413 	 */
414 	if (tq->tqi_flags & AR5K_TXQ_FLAG_TXOKINT_ENABLE)
415 		AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_txok, queue);
416 
417 	if (tq->tqi_flags & AR5K_TXQ_FLAG_TXERRINT_ENABLE)
418 		AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_txerr, queue);
419 
420 	if (tq->tqi_flags & AR5K_TXQ_FLAG_TXURNINT_ENABLE)
421 		AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_txurn, queue);
422 
423 	if (tq->tqi_flags & AR5K_TXQ_FLAG_TXDESCINT_ENABLE)
424 		AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_txdesc, queue);
425 
426 	if (tq->tqi_flags & AR5K_TXQ_FLAG_TXEOLINT_ENABLE)
427 		AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_txeol, queue);
428 
429 	if (tq->tqi_flags & AR5K_TXQ_FLAG_CBRORNINT_ENABLE)
430 		AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_cbrorn, queue);
431 
432 	if (tq->tqi_flags & AR5K_TXQ_FLAG_CBRURNINT_ENABLE)
433 		AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_cbrurn, queue);
434 
435 	if (tq->tqi_flags & AR5K_TXQ_FLAG_QTRIGINT_ENABLE)
436 		AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_qtrig, queue);
437 
438 	if (tq->tqi_flags & AR5K_TXQ_FLAG_TXNOFRMINT_ENABLE)
439 		AR5K_Q_ENABLE_BITS(ah->ah_txq_imr_nofrm, queue);
440 
441 	/* Update secondary interrupt mask registers */
442 
443 	/* Filter out inactive queues */
444 	ah->ah_txq_imr_txok &= ah->ah_txq_status;
445 	ah->ah_txq_imr_txerr &= ah->ah_txq_status;
446 	ah->ah_txq_imr_txurn &= ah->ah_txq_status;
447 	ah->ah_txq_imr_txdesc &= ah->ah_txq_status;
448 	ah->ah_txq_imr_txeol &= ah->ah_txq_status;
449 	ah->ah_txq_imr_cbrorn &= ah->ah_txq_status;
450 	ah->ah_txq_imr_cbrurn &= ah->ah_txq_status;
451 	ah->ah_txq_imr_qtrig &= ah->ah_txq_status;
452 	ah->ah_txq_imr_nofrm &= ah->ah_txq_status;
453 
454 	ath5k_hw_reg_write(ah, AR5K_REG_SM(ah->ah_txq_imr_txok,
455 					AR5K_SIMR0_QCU_TXOK) |
456 					AR5K_REG_SM(ah->ah_txq_imr_txdesc,
457 					AR5K_SIMR0_QCU_TXDESC),
458 					AR5K_SIMR0);
459 
460 	ath5k_hw_reg_write(ah, AR5K_REG_SM(ah->ah_txq_imr_txerr,
461 					AR5K_SIMR1_QCU_TXERR) |
462 					AR5K_REG_SM(ah->ah_txq_imr_txeol,
463 					AR5K_SIMR1_QCU_TXEOL),
464 					AR5K_SIMR1);
465 
466 	/* Update SIMR2 but don't overwrite rest simr2 settings */
467 	AR5K_REG_DISABLE_BITS(ah, AR5K_SIMR2, AR5K_SIMR2_QCU_TXURN);
468 	AR5K_REG_ENABLE_BITS(ah, AR5K_SIMR2,
469 				AR5K_REG_SM(ah->ah_txq_imr_txurn,
470 				AR5K_SIMR2_QCU_TXURN));
471 
472 	ath5k_hw_reg_write(ah, AR5K_REG_SM(ah->ah_txq_imr_cbrorn,
473 				AR5K_SIMR3_QCBRORN) |
474 				AR5K_REG_SM(ah->ah_txq_imr_cbrurn,
475 				AR5K_SIMR3_QCBRURN),
476 				AR5K_SIMR3);
477 
478 	ath5k_hw_reg_write(ah, AR5K_REG_SM(ah->ah_txq_imr_qtrig,
479 				AR5K_SIMR4_QTRIG), AR5K_SIMR4);
480 
481 	/* Set TXNOFRM_QCU for the queues with TXNOFRM enabled */
482 	ath5k_hw_reg_write(ah, AR5K_REG_SM(ah->ah_txq_imr_nofrm,
483 				AR5K_TXNOFRM_QCU), AR5K_TXNOFRM);
484 
485 	/* No queue has TXNOFRM enabled, disable the interrupt
486 	 * by setting AR5K_TXNOFRM to zero */
487 	if (ah->ah_txq_imr_nofrm == 0)
488 		ath5k_hw_reg_write(ah, 0, AR5K_TXNOFRM);
489 
490 	/* Set QCU mask for this DCU to save power */
491 	AR5K_REG_WRITE_Q(ah, AR5K_QUEUE_QCUMASK(queue), queue);
492 
493 	return 0;
494 }
495 
496 
497 /**************************\
498 * Global QCU/DCU functions *
499 \**************************/
500 
501 /**
502  * ath5k_hw_set_ifs_intervals  - Set global inter-frame spaces on DCU
503  *
504  * @ah The &struct ath5k_hw
505  * @slot_time Slot time in us
506  *
507  * Sets the global IFS intervals on DCU (also works on AR5210) for
508  * the given slot time and the current bwmode.
509  */
510 int ath5k_hw_set_ifs_intervals(struct ath5k_hw *ah, unsigned int slot_time)
511 {
512 	struct ieee80211_channel *channel = ah->ah_current_channel;
513 	struct ath5k_softc *sc = ah->ah_sc;
514 	struct ieee80211_rate *rate;
515 	u32 ack_tx_time, eifs, eifs_clock, sifs, sifs_clock;
516 	u32 slot_time_clock = ath5k_hw_htoclock(ah, slot_time);
517 
518 	if (slot_time < 6 || slot_time_clock > AR5K_SLOT_TIME_MAX)
519 		return -EINVAL;
520 
521 	sifs = ath5k_hw_get_default_sifs(ah);
522 	sifs_clock = ath5k_hw_htoclock(ah, sifs);
523 
524 	/* EIFS
525 	 * Txtime of ack at lowest rate + SIFS + DIFS
526 	 * (DIFS = SIFS + 2 * Slot time)
527 	 *
528 	 * Note: HAL has some predefined values for EIFS
529 	 * Turbo:   (37 + 2 * 6)
530 	 * Default: (74 + 2 * 9)
531 	 * Half:    (149 + 2 * 13)
532 	 * Quarter: (298 + 2 * 21)
533 	 *
534 	 * (74 + 2 * 6) for AR5210 default and turbo !
535 	 *
536 	 * According to the formula we have
537 	 * ack_tx_time = 25 for turbo and
538 	 * ack_tx_time = 42.5 * clock multiplier
539 	 * for default/half/quarter.
540 	 *
541 	 * This can't be right, 42 is what we would get
542 	 * from ath5k_hw_get_frame_dur_for_bwmode or
543 	 * ieee80211_generic_frame_duration for zero frame
544 	 * length and without SIFS !
545 	 *
546 	 * Also we have different lowest rate for 802.11a
547 	 */
548 	if (channel->hw_value & CHANNEL_5GHZ)
549 		rate = &sc->sbands[IEEE80211_BAND_5GHZ].bitrates[0];
550 	else
551 		rate = &sc->sbands[IEEE80211_BAND_2GHZ].bitrates[0];
552 
553 	ack_tx_time = ath5k_hw_get_frame_duration(ah, 10, rate);
554 
555 	/* ack_tx_time includes an SIFS already */
556 	eifs = ack_tx_time + sifs + 2 * slot_time;
557 	eifs_clock = ath5k_hw_htoclock(ah, eifs);
558 
559 	/* Set IFS settings on AR5210 */
560 	if (ah->ah_version == AR5K_AR5210) {
561 		u32 pifs, pifs_clock, difs, difs_clock;
562 
563 		/* Set slot time */
564 		ath5k_hw_reg_write(ah, slot_time_clock, AR5K_SLOT_TIME);
565 
566 		/* Set EIFS */
567 		eifs_clock = AR5K_REG_SM(eifs_clock, AR5K_IFS1_EIFS);
568 
569 		/* PIFS = Slot time + SIFS */
570 		pifs = slot_time + sifs;
571 		pifs_clock = ath5k_hw_htoclock(ah, pifs);
572 		pifs_clock = AR5K_REG_SM(pifs_clock, AR5K_IFS1_PIFS);
573 
574 		/* DIFS = SIFS + 2 * Slot time */
575 		difs = sifs + 2 * slot_time;
576 		difs_clock = ath5k_hw_htoclock(ah, difs);
577 
578 		/* Set SIFS/DIFS */
579 		ath5k_hw_reg_write(ah, (difs_clock <<
580 				AR5K_IFS0_DIFS_S) | sifs_clock,
581 				AR5K_IFS0);
582 
583 		/* Set PIFS/EIFS and preserve AR5K_INIT_CARR_SENSE_EN */
584 		ath5k_hw_reg_write(ah, pifs_clock | eifs_clock |
585 				(AR5K_INIT_CARR_SENSE_EN << AR5K_IFS1_CS_EN_S),
586 				AR5K_IFS1);
587 
588 		return 0;
589 	}
590 
591 	/* Set IFS slot time */
592 	ath5k_hw_reg_write(ah, slot_time_clock, AR5K_DCU_GBL_IFS_SLOT);
593 
594 	/* Set EIFS interval */
595 	ath5k_hw_reg_write(ah, eifs_clock, AR5K_DCU_GBL_IFS_EIFS);
596 
597 	/* Set SIFS interval in usecs */
598 	AR5K_REG_WRITE_BITS(ah, AR5K_DCU_GBL_IFS_MISC,
599 				AR5K_DCU_GBL_IFS_MISC_SIFS_DUR_USEC,
600 				sifs);
601 
602 	/* Set SIFS interval in clock cycles */
603 	ath5k_hw_reg_write(ah, sifs_clock, AR5K_DCU_GBL_IFS_SIFS);
604 
605 	return 0;
606 }
607 
608 
609 int ath5k_hw_init_queues(struct ath5k_hw *ah)
610 {
611 	int i, ret;
612 
613 	/* TODO: HW Compression support for data queues */
614 	/* TODO: Burst prefetch for data queues */
615 
616 	/*
617 	 * Reset queues and start beacon timers at the end of the reset routine
618 	 * This also sets QCU mask on each DCU for 1:1 qcu to dcu mapping
619 	 * Note: If we want we can assign multiple qcus on one dcu.
620 	 */
621 	if (ah->ah_version != AR5K_AR5210)
622 		for (i = 0; i < ah->ah_capabilities.cap_queues.q_tx_num; i++) {
623 			ret = ath5k_hw_reset_tx_queue(ah, i);
624 			if (ret) {
625 				ATH5K_ERR(ah->ah_sc,
626 					"failed to reset TX queue #%d\n", i);
627 				return ret;
628 			}
629 		}
630 	else
631 		/* No QCU/DCU on AR5210, just set tx
632 		 * retry limits. We set IFS parameters
633 		 * on ath5k_hw_set_ifs_intervals */
634 		ath5k_hw_set_tx_retry_limits(ah, 0);
635 
636 	/* Set the turbo flag when operating on 40MHz */
637 	if (ah->ah_bwmode == AR5K_BWMODE_40MHZ)
638 		AR5K_REG_ENABLE_BITS(ah, AR5K_DCU_GBL_IFS_MISC,
639 				AR5K_DCU_GBL_IFS_MISC_TURBO_MODE);
640 
641 	/* If we didn't set IFS timings through
642 	 * ath5k_hw_set_coverage_class make sure
643 	 * we set them here */
644 	if (!ah->ah_coverage_class) {
645 		unsigned int slot_time = ath5k_hw_get_default_slottime(ah);
646 		ath5k_hw_set_ifs_intervals(ah, slot_time);
647 	}
648 
649 	return 0;
650 }
651